The first Earth Day in 1970 marked the start of a global environmental consciousness. The chartering of the Environmental Protection Agency (EPA) later that year represented a new federal commitment to preserving the environment. Congress passed the Federal Water Pollution Control Act (also known as the Clean Water Act) in 1972. This complex law required that every stream meet designated water quality standards based on type of use. To meet these new guidelines, the City began an upgrade of its sewage treatment processes that took 15 years and cost more than $1 billion. - from PWD's Water and Drainage History course, © 2015 Philadelphia Water Department.